This application claims the priority of German application 197 33 473.3, filed Aug. 2, 1997 in Germany, the disclosure of which is expressly incorporated by reference herein.
The present invention concerns a process for producing a linkage or connection between a hollow cylindrical air/fuel ratio detector holder and an exhaust pipe which acquires a desired finished shape through internal high-pressure forming or "remodeling" of a blank piece, and a device or apparatus for carrying out the process.
Air/fuel ratio detector holders are known in manifold types, as shown for example, in DE 34 09 045 C1. In all of these known configurations, the holder is fitted specifically to the curved shape of the exhaust pipe in order to attain a dimensionally stable link between the holder and the exhaust pipe. This guarantees that a subsequent welding of the holder to the exhaust pipe creates a connection which withstands mechanical and thermal stress. The specific fitting process is, however, expensive in terms of production technology and is thus cost-intensive. In particular, in tight component space conditions, in which the hollow cylindrical holder is forced to be fastened with its casing to the exhaust pipe, this can be accomplished accurately only either through a highly complicated contour milling of the casing of the holder, or through forming the holder as a precision cast part whose contour structure is shaped during the casting procedure. Both methods demand expensive tools and involve long processing times. This also causes increased costs in the shaping of an appropriate link between the holder and the exhaust pipe.